text: The HRM methodology has also been exploited to provide a reliable analysis of the methylation status of DNA.  This is of significance since changes to the methylation status of tumour suppressor genes, genes that regulate apoptosis and DNA repair, are characteristics of cancers and also have implications for responses to chemotherapy.  For example, cancer patients can be more sensitive to treatment with DNA alkylating agents if the promoter of the DNA repair gene MGMT of the patient is methylated. In a study which tested the methylation status of the MGMT promoter on 19 colorectal samples, 8 samples were found to be methylated. Another study compared the predictive power of MGMT promoter methylation in 83 high grade glioma patients obtained by either MSP, pyrosequencing, and HRM. The HRM method was found to be at least equivalent to pyrosequencing in quantifying the methylation level.
  Methylated DNA can be treated by bi-sulphite modification, which converts non-methylated cytosines to uracil.  Therefore,  PCR products resulting from a template that was originally unmethylated will have a lower melting point than those derived from a methylated template. HRM also offers the possibility of determining the proportion of methylation in a given sample, by comparing it to a standard curve which is generated by mixing different ratios of methylated and non-methylated DNA together. This can offer information regarding the degree of methylation that a tumour may have and thus give an indication of the character of the tumour and how far it deviates from what is "normal".
  HRM also is practically advantageous for use in diagnostics, due to its capacity to be adapted to high throughput screening testing, and again it minimises the possibility of amplicon spread and contamination within a laboratory, owing to its closed-tube format.